Mechanism for truing and dressing grinding wheels of centerless grinders



y 31, 1932- F. J. HOHNHORST ET AL 1,860,614

MECHANISM FOR TRUING AND DRESSING GRINDING WHEELS OF CENTERLESS GRINDERSFiled March 14, 1950 5 Sheets-Sheet l II III \llllllH y 3 1932- F. J.HOHNHORST E AL 1,860,614

MECHANISM FOR TRUING AND DRESSING GRINDING WHEELS OF CENTERLES SGRINDERS 5 Sheets-Sheet 2 Filed March 14, 1930 [N ENTORS y 1932- F. J.HOHNHORST ET AL 1,860,514

MECHA M FOR TRUING AND DRESSING GRINDING EELS OF CENTERLESS GRINDERS IFiled March 14,

1950 3 Sheets-Sheet 3 Patented May 31, 1932 UNITED; STA

res PATENT OFFICE FERDINAND .rizionmions'r, AND FERDINAND Jfk oEeEn, FcovIiveroN, KENTUCKY machines,

. means MEC ANISM son TRUING annnnnssme GRINDING WHEELS or CENTERLESS'emmmns 1 v 1 Application filed March '14, .1930. Serial K014355823.

Our invention relates to mechanism for truing and dressing grindingwheelsi such as emery wheels, including carborundum wheels. and thelike, in centerless grinding in which the work is rotated by peripheralcontact with the peripheries of op posed grindingwheels rotating atdifierent p ed The'grinding wheels employed in grinding metals andsimilar hard substances in ma- .chi'nes-of this character are compositegrinding wheels containing comminuted or finely divided emery,carborundum or other cutting medium and a suitable bond, suitably .boundtogether as a composite mass, the fine: ness of the grains of thecutting medium determiningthe-coarsenessor fineness of the g nd g-.1 V yI It is the object of our invention to prov de novel-means for truing oringsurface of the grinding wheel or 'wheels in a machine of thischaracter; further,to provide a composite abrading wheel and .meanswhereby. to present the composite 'abrading wheel to the grindingsurface of the grindingwheel under thehoodof the grinding wheel;further, to provide novel means for supporting the abrading wheel;further, to'provide novel means fortraversing the support of the abrading wheel while projecting through the hood of the grinding wheel;further, to provide any abrading wheel .and means for mountingthesame atan angle to the periphery-of the grinding wheel under the hood of thegrinding wheel; and, further, to-provide novel mounting for theabradingwheel extending through aslotin the hood of the grinding wheelfor permitting lateraladjustment of the abrading wheel across the {faceof the I grinding-wheel and a slide movablewith said mounting; formaintaining closedrelation of 7 said slot to prevent the passageof'grinding dustand particles therethrough.

The invention will be further readily unfderstood from the followingdescription and claim, and from the drawings, in which latter I Fig. 1is a slde elevation of an exemplifying dressing the grind the spacebetween the grinding, wheels. structure and form ofthe support isdepend- ;centerless grinding machine embodying our invention, partlybroken away.

Fig. 2 is a plan vlew of the same, partly broken away.

device, taken on the line of Fig. 2. Fig. 4 is a cross-section showingan exemplifiedbearlng means for the abrading wheel of our improveddevice taken on the line 4- 1 ofFig. 3. Fig. 5 is a cross-section takenin the plane of the line 5-5 of *Fig. 8, with the closing plate removed.

Fig. Gis'a cross-section showing the clamping means for the sleeve takenon the line 66 of Fig. 2; and,

Fig. 7 is an axial sectiompartly broken :away, showing a modification ofour improved device. r z I v The exemplified centerless grinding machine comprises a frame 11 which has a hearing 12 in which the shaft 13of a grindingwheel 14 rotates. The shaft is suitably driven, and thegrinding wheel is suitably releasably secured to the shaft. Thisgrinding wheel is the mainv grinding wheel of the cou- 19 on the mainframetowardand from the grinding wheel 14. The means for adjusting andmoving the auxiliary grinding wheelare not shown because wellknown.

A' support 21 for the work entzonthe work to be ground. 7 r

, Ahood 25 is received aboutthe grindingv wheel 14, anda hood 25 isreceived -about the grinding wheel 15. These hoods-encomor dressingmeans are respectively mounted on the respective hoods and projectthrough said'hoods. They may beyoffsimilarconstruction, although onema'ydiffer from the other in non-essential details. The abrading is locatedin .The

Fig. 3 isan axial section of our improved 5 pass the ma or'portions ofthe peripheries of ing ing a guideway 28 on which a slide 29 is arrangedto moi e laterallywith relation tothe plane of the grinding wheel 14.

' A screw-shaft 31 is journaled in a bearing 32 on the guide and is heldendwise therein, the screw-rod being threaded in a threaded nut 33 fixedon the slide. A hand-wheel 34: 'isfixed to the screw-rod for rotatingthe same and thereby moving the slide laterally.

The slide is provided with a bearing 35 in "which asleeve 36 isadjustable axially. The sleeveis arranged to be clamped in adjustedpositions in the bearing by means of a clampshoe 30clampingly acted onby a clamp-bolt "37. This sleeve is preferably movable axially in saidbearing toward and from the grinding-wheel in the hood for locating theabrading wheel 38 in approximate position with relation to the grindingwheel.

The sleeve is provided with a bore 39 in "which'there is a shank 40 of amountin for the abradin wheel. This shank is a ]ustable axially 1n thesleeve, as by providing the Shank with an axially threaded portion 41,in which a feed-screw 42 is threaded. The "feed-screw has ajournal-portion 43 in an axial bearing 44 'at the outer end of thesleeve, and isprovided with a hand-wheel 45 for r0- tating thefeed-screw. The feed-screw is held endwise in its bearing by locatingthe be-aringbetween a collar 46 on the feed-screw and'the'hub of theadjusting wheel 45. The

- earing is secured to the end of the sleeve, as

with means by means of screws 47. The inner end of the shank is providedforsecuring the abradlng part thereto. These are exemplified ascomprisinga fork 51 having axhood 52. The fork provide'dwithbearings 53.IAn axle 54'is in said bearings, as by nieansof clampbolts 55securingthecaps 5 6 ofsaid bearings so the fork5l of said shank ormounting for fheabrading wheel. I A shell 61 has ball-bearings 62,63,64, 65, therein, arranged in pairs, the outer raceways of the pairsbeing separated by. a ring 66. A plug '67 is threaded in the shell andclamps the. outer'raceways and ring between a ShouIderBB'inthe shell andsaid plug.

The axle is provided 'wth a flange 69 10- cated'between the'innerraceways of the respective pairs of ball-bearings. Annular said hole.

spaces 70 are located between the outer ends of said inner raceways andthe end Wall 71 and said plug 67 respectively. Said wall and plug areprovided with inner peripheries 72 making close joint connection withthe outer periphery of said axle. I

The axe is provided with a passage 74 having a branch 75 connecting withthe space 76 in said shell and with a branch 77 connecting with thepassage78 in one of thebearings 53, the outer end of the latter passagebein provided with a lubricant fitting 79 througl i which lubricant maybe introduced through the passages and into said hollow of the shell forlubricating the bearing.

The abrading wheel is a composite abrading wheel comprising grains ofemery, carborundum or other cutting medium of suitable fineness,dependent onthe fineness of the work to be done, and a suitable bond, a

suitably bound together as a composite mass, preferably of a texturemuch'harder than the texture of the grinding wheel, and of substantiallysmaller diameter than the grinding wheel.

The abrading wheel is rotated by peripheral contact with the peripheryof the grinding wheel. It is preferably held ina plane at an angle tothe plane of the grinding wheel.

The grinding wheel during operation 'be- It comes impregnated withparticles of dirt or metal from the work being operated on and becomecomparatively glossy and thereby loses itsgrinding effect, its granularstructure also becoming dull at the grinding'face, thereby reducing itsgrinding or polishing properties.

.By means of our invention particles of dirt and metal are removed fromthegrinding surface of the grinding wheel by coaction of the rotaryabrading wheeltherewith whereby to clear'the recesses and pores in thegrinding surface, and the partlcles or grams in the abrading surface aresharpened.

In order to maintain the abradin wheel at an angle with relation tothegrin ing wheel there a spline groove and key connection 81 between theshank 40 and the sleeve 36.

The shank passes through a slot 82 in the hood. A plate 83 normallycloses said slot and is arranged to slide'laterally in a guide 84 onsaid hood. The plate is provided with'an outward bulge 85 in which thereis a h0le'86. The inner end of the sleeve is received through said holein said plate, and is ad justable axially in said hole by axial adjust-I ment of the sleeve in its bearing 35. .The sleeve normally closes saidhole so as to prevent the passage of dust and dirt through The bulgeaccommodates the fork 51, the hood 52, and the abrading wheel and otherparts mounted in the fork, throughout the various adjustments of theabrading wheel.

When itis desired to true or to dress the grinding wheel the sleeve36 isadjusted axially in its bearing 35 and in the hole 85 for approximatelypositioning the abrading wheel with relation to the grinding wheel, thesleeve being clamped in such position in said bearing, The hand-wheel isthen turned for obtaining the proper contact between the abrading wheeland the grinding wheel. The grinding wheel being rotated byits usual vpower drive causes rotation of the abrading wheel by peripheral contacttherewith. The relative positioning, between'the abrading wheel and thegrinding wheel causes a wiping action between the periphery of theabrading wheel and the periphery of the grinding wheel for truing anddressing the latter.

During such operation the abrading wheel is moved laterally across thewidth of the grinding wheel by manipulation of the handwheel 34, wherebythe slide 29 and the abrading wheel 38 are shifted laterally on thehood.

This lateral shifting also causes lateral movement of the plate 83 inits guide, the plate throughout all its adjustments maintaining the slot82 closed;

If desired, a composite abrading stub or pencil 91 made of compositionsimilar to that of the abrading wheel may be mounted in a socket 92 inthe inner end of a shank 1&0 and fixed therein by a set-screw 93. Thisstub or pencil may have a contour at its contact end [with the grindingwheel of suitable shape for imparting a desired peripheral contour tothe grinding wheel, if it is desired to impart a shape to the grindingwheel other than cylindrical. Such an arrangement is illust-rated inFig. 7 in which parts are shown similar to those above described butraised to the series 100.

Our improved device is simple in construction and operation and providesmeans whereby the dressing or truing of the grinding wheel may bequickly accomplished and dis- I penses with the use of expensivediamonds by Letters Patent, is:

which have been heretofore employed for the purpose.

Having thus fully described our invention,

what we claim as new, and desire to secure In a machine of the characterdescribed,

y the combination of a grinding wheel, a hood therefor, an ,abradingwheel operatively 1ocatedbetween said hood andsaid grinding. wheel, .amounting for said abrading Wheel comprising a fork, a sleeve and ashank; said. fork fixed to the inner end of said shank, a guide-on saidhood, a laterally movable slide on said guide, means on said slide forsecurrotative in saiddeeve for holding and main- I taining said fork andsaid bearing means for said abrading wheel at an angle to the plane ofsaid grinding Wheel, means for adjusting said shank in said sleeve, saidhood provided with a slot, and a cover plate for said slot having slideconnectionwith said hood, said cover plate provided with an upwardlyex-,

I said shank, said angularly positioned fork, said-bearing means andsaid abrading wheel,

said cover plate movable laterally on said hood with said mounting, andsaid cover plate with its bulge maintaining said slot in closed relationthroughout the lateral movements of said abrading wheel.

In testimony whereof, we have hereunto signed our names.

FERDINAND J HOHNHORST. FERDINAND J. KROEGER.

